The present invention relates to radar systems, and more particularly to a method and system for compensating for radar platform angular motion in a phased array radar or the like.
Electronically scanned array (ESA) radar antennas provide many benefits in terms of beam control flexibility, antenna efficiency, and effective power delivery with no mechanically moving parts. Maximum tracking sensitivity and accuracy may be achieved through maximizing the signal to noise ratio by applying coherent integration over as long a dwell as feasible and limited by target Doppler spread and uncertainties in radar platform and target velocity change rates (acceleration). However when operated on board a missile, airframe, or other mobile platform with high levels of body roll and/or pitch and yaw rates, the body fixed (“strapdown”) radar platform angular motion during the dwell spreads the angle measurement processing, such as monopulse beams, and exposes the angle measurement process to errors and reduced sensitivity through combinations of monopulse error slope nonlinearities, signal power variations during the dwell, and interfering effects from signals received from non-target sources, such as clutter, other targets, electronic countermeasures or similar sources. Antenna gains may also be reduced by the smearing. Since the antenna face may not be perpendicular to a line-of-sight to the target (for off-axis tracking), platform roll may also produce differential Doppler responses over the face of the array. This may result in Doppler spreading that reduces Doppler resolution and discrimination.